Electronic yarn guard for yarn-winding devices

ABSTRACT

For use with a yarn-winding device wherein the yarn being wound is reciprocated between two spaced reversing nodes, an electronic yarn guard comprising a yarn-sensing member disposed in a region located between the reversing nodes.

United States Patent [72] Inventor Walter Glth Monchenghdbuh, Germany [211 App]. No. 685,065 [22] Filed Nov. 22, 1967 [45] Patented July 13, 1971 [73] Assignee Walter Reiners Monchengladbnch, Germany [32] Priority Nov. 23, 1966 [33] Germany [31] R 44 637 [54] ELECTIONIC YARN GUARD FOR YARN- WIND ING DEVICES 5 Claims. 3 Drawing Figs.

[52] 0.8. CI 242/36 [51] Int. Cl. B651! 63/00 [50] Field of Search...... H 242/36, 37,

[56] Relerences Cited UNITED STATES PATENTS 2,506, I 74 5/1950 Price 242/36 X Primary Emminer-Stan1ey Nv Gilreath Attorneys-Curt M. Avery, Arthur E. Wilfond, Herbert L.

Lerner and Daniel J. Tick ABSTRACT: For use with a yam-winding device wherein the yarn being wound is reciprocated between two spaced reversing nodes, an electronic yarn guard comprising a yamsensing member disposed in a region located between the reversing nodes.

PATENTEU JUL 1 3 l9?! 3; 592.400

INVAWI'OR mm! ELECTRONIC YARN GUARD FOR YARN-WINDING DEVICES My invention relates to an electronic yarn guard for yarnwinding devices wherein the yarn being wound is reciprocated between a pair of spaced reversing nodes.

Since the rate of response of mechanical yarn guards with increasing winding velocity is not rapid enough due to the inertia of the mechanical yarn guards, electronic yarn guards for yarn-winding devices have been developed wherein optical, capacitive, piezoelectrical, or electromechanical measuring or sensing members are employed. In the Swiss Pat.402,462 there is described, for example, an electronic yarn guard having a capacitive sensor. The sensor is formed in a known manner of two capacitor coatings, in the electrical field of which the yarns that are to be controlled or supervised are located. When a yarn break occurs, the yarn leaves the electrical field so that the capacitance of the sensing member is altered. This change in capacitance serves for indicating the occurrence of the yarn break.

In the heretofore-known devices of this general type, the sensing member is located in that part of the yarn path wherein the yarn is guided in substantially a straight line. Accordingly, the presence of the yarn is always maintained in relation to a predetermined nominal value, such as, for example, to a capacitance value for capacitive sensing members, to a predetermined amount of shadow for optical sensing members, and the like. A disadvantage of these heretofore-known devices is that these relative values are subject to considerable fluctuations produced for example with capacitive measuring members by variation in the moisture content of the yarn or of the air, and for optical measuring members by the influence of extraneous stray light beams. In order to avoid the sources of error caused by the foregoing, a relatively great expense is required.

It is accordingly an object of my invention to provide an electronic yarn guard for yarn-winding devices which is independent of the aforementioned disturbing influences so that expensive stabilizing and auxiliary control devices are not required.

With the foregoing and other objects in view I accordingly provide for use with a yarn-winding device wherein the yarn being wound is reciprocated transversely or laterally between two spaced reversing nodes during forward winding travel, an electronic yarn guard comprising a yarn-sensing member disposed in a region located between the reversing nodes.

As long as the yarn travels it produces an alternating current in the sensing member due to the reciprocatory movement thereof. The instant the yarn is broken, and has left the sensing member, no further alternating current is produced. The associated measuring device need not indicate any accurate measuring values or results but is required only to distinguish whether or not an alternating current is produced.

Other features which are considered as characteristic for the invention are set fort in the appended claims.

Although the invention is illustrated and described herein as embodied in electronic yarn guard for yarn-winding devices, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The construction and method of operation ofthe invention, however, together with additional objects an advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIGS. 1 and 2 are diagrammatic views of two different embodiments of my invention; and

FIG. 3 is a plan view of the sensing member of FIG. 2 taken in the direction of the arrow Ill.

Referring now to the drawing and first particularly to FIGS. I and 2 thereof, there is schematically shown a cheese or crosswound coil-winding machine. A yarn package or cheese 3 is mounted on the upper end of the frame I of the coil-winding machine. The yarn package 3 is rotatably driven by the yarn-guiding drum 2 of the coil-winding machine. As may be noted from both FIGS. I and 2, the yarn being wound on the yarn package 3 passes from a final guide member 4, such as a tensioner or a yarn eye for example, across an intervening space and onto the yarn-guiding drum 2. The yarn-guiding drum 2 is formed in a conventional manner with an endless guiding groove within which the yarn is received, and is reciprocated in the direction of the drum axis between the limit positions F and F shown in FIGS. I and 2. In the respective positions F and F", the yarn is located at a reversing node of the endless guiding groove, at which node respectively a reversal in the direction of movement of the yarn occurs. In accordance with my invention, a yarn-measuring or sensing member of an electronic yarn guard is located alongside the yarn-guidin'g drum 2 in the region between the reversing nodes of the guiding groove thereof or between the limit positions F and F" of the yarn.

In the embodiment of FIG. I there is provided an optical measuring or sensing member formed of a lamp 5 producing a light beam 6 which impinges on a light-sensitive cell 7 such as a photoelement, photodiode, photocell or the like. The light beam 6 extends in the direction of reciprocatory movement of the yarn F, F". Depending upon the position F or F" assumed by the yarn, the photosensitive element 7 will be subjected to a greater or lesser shadow, i.e. will receive either less or more light, respectively, from the lamp 5, as the yarn F, F" passes between the lamp and the photosensitive element 7. The continual variation in the amount of shadow cast by the reciprocating yarn onto the photosensitive element 7 produces an alternating current in the latter, which is amplifiable in a conventional manner and can be applied to a suitable indicating device for determining the existing yarn path or position.

In the embodiment of FIG. 2 there is provided a capacitive measuring or sensing element 8 having a field of measurement extending perpendicularly to the direction of reciprocatory movement of the yarn F, F". As shown more clearly in FIG. 3, which is a plan view of the capacitive sensing element 8 of FIG. 2 as seen in the direction of the arrow III in FIG. 2, the sensing element 8 includes two capacitor plates 9 and II) which are, for example, embedded in holders 9a and Illa, respectively, consisting of plastic material or any other suitable nonconductive material. The plastic holders 9a and 10a are formed with contours 9b and 9c on the one hand and 10b and on the other hand which permit convenient threading and ensure proper guidance of the yarn between the holders 9a and Illa and the respective capacitor plates 9 and II). The space between the holders 9a and 10a accordingly has an hourglass shape. The plastic holders 9a and I00 are attached by screws II and 12 to a support plate I3 of insulating material. Electrical leads 9b and Illd connected to the capacitor plates 9 and 10, respectively, on the one hand, and to the screws II and 12, respectively, on the other hand, are also embedded in the plastic holders )0 and Illa, respectively. The screws II and I2 also serve as terminals for a nonillustrated amplifier to which the measurement leads 9d and 10d apply the changing signal from the capacitor plates 9 and I0 caused by the presence or absence of the yarn therebetween.

Of course, other embodiments that are within the scope of my invention can also be produced, having either a different construction of the measuring or sensing device from those hereinbefore described or a different arrangement or disposition thereof. For example, the optical sensing member 5, 7 of FIG. I can be located so that the light beam 6 is perpendicular to the direction of reciprocatory movement of the yarn. It is also possible to connect several sensing members in parallel or in series with one another within the region located between the reversing nodes of the yarn-guiding drum 2 so as to obtain pulses of greater amplitude or higher frequency. It is also to be noted again that with the device of the instant application, in contrast to the heretofore known devices of this general type, there is no concern with nor need for obtaining exact mea surement values so that the amplifier that is required for amplifying the signal from the sensing member of the device can, for example, be constructed of relatively simple components and need not be a sophisticated and exceedingly accurate reproducing instrument. Just as the moisture content of the yarns or ofthe surrounding air is immaterial for the measuring values or results when employing capacitive measuring or sensing devices in accordance with my invention, disruptive extraneous light from sources other than the lamp of the optical measuring or sensing members no longer has the effect on such optical sensors, when employed in accordance with my invention, as on those of the heretofore known electronic yarn guards. Since the amplifier to be employed with the device of my invention need only distinguish between on and "of so to speak, a single, common high frequency generator can be used for all sensing locations in all of the winding stations of multistation yarn-winding machines, and an additional high frequency current conductor for the yarn guard can be inserted in the common current supply cable to the high frequency generator. Thus, at each winding station, a branch of the high frequency current conductor can be connected to the electronic yarn guard, since the differences in the high frequency signal as shown on a suitable indicator, in the case ofthe instant invention which, as aforementioned, requires no accurate measurements, are of no significance.

An especially great advantage of the yarn guard according to my invention is that a yarn break is detected even when the yarn does not leave the sensing member but remains hanging therein for some reason. In the heretofore known devices, a yarn which remains hanging in the sensing member after a break occurs therein gives the impression that it is traveling in the regular travel path of the yarn. Consequently, the hereto fore-known yarn guards cannot fulfill their required objectives under all conditions without difficulty. On the other hand, with the yarn guard of the instant application, a yarn remaining hanging in the sensing member after the occurrence of a yarn break, will nevertheless not be reciprocated between the reversing nodes of the yarn guide drum so that no alternating current will be produced, thereby assuring a reliable indica tion of the yarn breakv I claim:

1, For use with a yarn'winding device wherein the yarn being wound is reciprocated between two spaced reversing node portions of a yarn-guiding device and is swept over a sub stantially triangular area defined by said reversing node portions and a yarn guide member located upstream thereof in the winding travel direction of the yarn, an electronic yarn guard comprising a yarn-sensing member disposed in a region located between the reversing node portions and forward of said yarn guide member in said winding travel direction of the yarn so as to sense the yarn in the triangular areas 2. For use with a yarn-winding device wherein the yarn being wound is reciprocated between two spaced reversing nodes and is swept over a substantially triangular area defined by said reversing nodes and a point located upstream thereof in the winding travel direction of the yarn, an electronic yarn guard comprising a yarn-sensing member disposed in a region located between the reversing nodes and forward of said point in said winding travel direction of the yarn, said reversing nodes being in an endless groove formed in a yarn-guiding drum and a yarn guide member being located at said point and spaced upstream of the winding travel direction of the yarn from the yarn-guiding drum, said yarn-sensing member being located in the space between the yarn guide member and the yarn-guiding drum.

3. Yarn guard according to claim 1 wherein said sensing member comprises means responsive to the reciprocations of the yarn between the two reversing node portions for producing an alternating current output having a frequency corresponding to the reciprocationsof the yarn. I

, For use with a yarn-wind|ng device wherein the yarn being wound is reciprocated between two spaced reversing nodes, an electronic yarn guard comprising a yarn-sensing member disposed in a region located between the reversing nodes, said sensing member being a photoelectric sensor and comprising a constant light source and a photosensitive element adapted to receive light energy from said source, the yarn being movable in accordance with the reciprocations thereof between said light source and said photosensitive element so as to cast a shadow of varying size on said photosensitive element whereby an alternating voltage output is produced by said photosensitive element.

5, For use with a yarn-winding device wherein the yarn being wound is reciprocated between two spaced reversing node,, an electronic yarn guard comprising a yarn-sensing member disposed in a region located between the reversing nodes, said sensing member being a capacitive sensor and comprising a pair of spaced capacitor plates carried by respective elongated holders of electrically insulating material, the yarn being movable in accordance with the reciprocations thereof in the space between said holders and past said capacitor plates so as to vary the capacitance of said capacitor plates whereby an alternating voltage output is produced by said capacitive sensor. 

1. For use with a yarn-winding device wherein the yarn being wound is reciprocated between two spaced reversing node portions of a yarn-guiding device and is swept over a substantially triangular area defined by said reversing node portions and a yarn guide member located upstream thereof in the winding travel direction of the yarn, an electronic yarn guard comprising a yarn-sensing member disposed in a region located between the reversing node portions and forward of said yarn guide member in said winding travel direction of the yarn so as to sense the yarn in the triangular area.
 2. For use with a yarn-winding device wherein the yarn being wound is reciprocated between two spaced reversing nodes and is swept over a substantially triangular area defined by said reversing nodes and a point located upstream thereof in the winding travel direction of the yarn, an electronic yarn guard comprising a yarn-sensing member disposed in a region located between the reversing nodes and forward of said point in said winding travel direction of the yarn, said reversing nodes being in an endless groove formed in a yarn-guiding drum and a yarn guide member being located at said point and spaced upstream of the winding travel direction of the yarn from the yarn-guiding drum, said yarn-sensing member being located in the space between the yarn guide member and the yarn-guiding drum.
 3. Yarn guard according to claim 1 wherein said sensing member comprises means responsive to the reciprocations of the yarn between the two reversing node portions for producing an alternating current output having a frequency corresponding to the reciprocations of the yarn.
 4. For use with a yarn-winding device wherein the yarn being wound is reciprocated between two spaced reversing nodes, an electronic yarn guard comprising a yarn-sensing member disposed in a region located between the reversing nodes, said sensing member being a photoelectric sensor and comprising a constant light source and a photosensitive element adapted to receive light energy from said source, the yarn being movable in accordance with the reciprocations thereof between said light source and said photosensitive element so as to cast a shadow of varying size on said photosensitive element whereby an alternating voltage output is produced by said photosensitive element.
 5. For use with a yarn-winding device wherein the yarn being wound is reciprocated between two spaced reversing node,, an electronic yarn guard comprising a yarn-sensing member disposed in a region located between the reversing nodes, said sensing member being a capacitive sensor and comprising a pair of spaced capacitor plates carried by respective elongated holders of electrically insulating material, the yarn being movable in accordance with the reciprocations thereof in the space between said holders and past said capacitor plates so as to vary the capacitance of said capacitor plates whereby an alternating voltage output is produced by said capacitive sensor. 